There is a very active rumor right now that American Girl plans to retire Caroline this year. Caroline was released in 2012 and seems to sell well.
It seems that the possible archival could be a result of a pending lawsuit in Canada over the name Caroline. With American Girl expanding into Canada and Mexico its not surprising that they would run into at least one trademark conflict, it happened to Journey Girls and Springfield dolls as well. You can read the news article here.
How do you feel about the possible archival of Caroline?